French Maran getting picked on and not laying for over a week

hi all, i have a 4 hens, french maran, bluebell, babcock brown and an amber star. Had them about 2 months and they are all 6 months old, They matured together and have been sorting out the pecking order. Initially the french maran and the bluebell were trying to install dominance. A week or two ago we saw that the french maran had lost some feathers from her behind, and noticed she had lost some from her tail end. It became apparent the bluebell was pecking her. We have a coup with dust bath, often provide hanging cabbages to challenge them, they are let out of the run for at least 5 hours a day (its summer hours in UK now) we even hung a polystyrene cube to detract bluebell. we also put some vicks vapour rub (not sure you have it in the US) but its eucalyptus strong smelling to prevent more pecking on the tail end of the french maran. We have stemmed it a little, however the FM is still a little disengaged from the group, doesn't come out of the hen house as fast as the others, always last and a bit mopey. Doesn't want to have morning feed with the others. Does eat during the day with them. She is always first in the hen house at night. She is pooping ok but hasn't laid an egg for nearly a week and am a bit concerned how long she could go without laying an egg and being what we think is a bit depressed. However she still runs up to us when we have food etc. Anyone have any advice on the lack of eggs and how long that can last and any other ideas about getting her mojo back?

Chickens will peck an unwell member or anyone acting odd. She may have something wrong with her, but without further symptoms it can be hard to say why. You could separate her within sight of the others or within the coop to see if she comes around and to keep her from getting pecked, until she either improves or you figure out what is wrong.

thanks for the response, its an odd one as she isnt really showing any major symptoms of anything. a little straining when pooping but not all the time. just a little dejected at times. she does seem less happy to be handled now. will keep monitoring but may take her to a vet if we cant work it out

Unfortunately, the mere sight of bare skin can encourage another bird to peck at her. The Vicks is good, but you might also try something like Blu-Kote. It's an antiseptic wound spray with (I think) gentian violet, so it's that bright blue/purple color. That masks the color of the bare skin and deters the other birds from pecking.

But that's only symptom treatment. Any chance she's flirting with being broody? Sitting on the nest a lot, growling when you approach her, all fluffed out?

Any recent changes in weather, etc that may be effecting her? Sounds like everyone else is healthy and productive?

well, she does seem to have some runny poop and seems to hold her position whilst doing it. have taken some local advice around keeping them in the run first thing in the morning to ensure she is eating the protein pellets. she didnt seem to eat too much this morning. it has been a bit warmer but as i am in UK it isnt really extreme as some of the US temperatures i read on here! She isnt happy around getting handled considering she was the friendliest chook we had previously but we thought that might just be because she has been picked on a bit. I do think there is some digestive issues considering her poop. i will see if there is anything i can put in her water to try and treat that.